i893. ON PASTEUR'S METHOD OF INOCULATION. 109 



Since there is no proof that the toxic principle is retained in the 

 body — indeed, it has been shown that in a diseased or vaccinated 

 animal the toxic products are eliminated in the urine — immunity con- 

 ferred by inoculation, if of more than momentary duration, cannot be 

 due to the actual presence of the poison. 



M. Bouchard, 9 again, has shown that the toxic products of 

 bacterial growth contain two antagonistic principles, which he has 

 termed anectasine and edasine. Possibly these may correspond to the 

 two principles of MM. Rodet and Courmont. 



According to Cohnheim, the passage of the white corpuscles of 

 the blood through the vessels (diapedesis) is the dominant pheno- 

 menon of inflammation ; and, according to MM. Massart and 

 Brodet, these white corpuscles possess a certain chemical irritability, 

 which causes them, when placed in solutions containing the products 

 of bacterial growth, to pass from those parts where the solution is 

 more dilute to those where it is more concentrated. These facts are 

 connected in an interesting manner with inoculation. 



Local inflammation is one of its phenomena, and it may be 

 supposed that the attractive action of the toxic principle of the 

 vaccine has caused diapedesis of the leucocytes. 



According to M. Bouchard, however, it is only the principle he 

 has named ectasine which promotes diapedesis ; the other, anecta- 

 sine, hinders it, and has been used by him for the prevention of 

 haemorrhage. When the leucocytes, thus drawn to the seat of local 

 inflammation, meet with any microbes, they envelop and digest them. 

 This is the phenomenon of phagocytosis. It may be held to explain 

 a temporary immunity from disease when subject to infection ; for 

 supposing an animal is inoculated with the toxic principle, then the 

 leucocytes are drawn to the seat of inoculation by the attractive force 

 of the ectasine. In their consequent state of activity, and outside 

 their proper vessels, they are in a favourable state for meeting with 

 and destroying, accidentally or purposely, introduced microbes. This 

 would explain immunity from disease existing immediately after inocula- 

 tion, which is, perhaps, all that has really been experimentally 

 proved. But it can scarcely be supposed that this abnormal activity 

 of the leucocytes, and their readiness to attack the microbes, could be 

 retained for any length of time. 



It may be further added that Pasteur himself has expressed his 

 conviction that the vaccinal matter of rabies is really a toxic prin- 

 ciple produced by the microbe, and that in the case of the spinal cord 

 of the rabbit exposed to heat and dry air, the microbe is destroyed 

 and not modified. 



G. W. BULMAN. 



9 Comptes Rendiis, vol. cxiii., p. 624. 



